Two chimeric regulators of G-protein signaling (RGS) proteins differentially modulate soybean heterotrimeric G-protein cycle

Heterotrimeric G-proteins and the regulator of G-protein signaling (RGS) proteins, which accelerate the inherent GTPase activity of Gα proteins, are common in animals and encoded by large gene families; however, in plants G-protein signaling is thought to be more limited in scope. For example, Arabidopsis thaliana contains one Gα, one Gβ, three Gγ, and one RGS protein. Recent examination of the Glycine max (soybean) genome reveals a larger set of G-protein-related genes and raises the possibility of more intricate G-protein networks than previously observed in plants. Stopped-flow analysis of GTP-binding and GDP/GTP exchange for the four soybean Gα proteins (GmGα1-4) reveals differences in their kinetic properties. The soybean genome encodes two chimeric RGS proteins with an N-terminal seven transmembrane domain and a C-terminal RGS box. Both GmRGS interact with each of the four GmGα and regulate their GTPase activity. The GTPase-accelerating activities of GmRGS1 and -2 differ for each GmGα, suggesting more than one possible rate of the G-protein cycle initiated by each of the Gα proteins. The differential effects of GmRGS1 and GmRGS2 on GmGα1-4 result from a single valine versus alanine difference. The emerging picture suggests complex regulation of the G-protein cycle in soybean and in other plants with expanded G-protein networks.     

Diversity and partitioning of bacterial populations within the accessory nidamental gland of the squid Euprymna scolopes

Microbial consortia confer important benefits to animal and plant hosts, and model associations are necessary to examine these types of host/microbe interactions. The accessory nidamental gland (ANG) is a female reproductive organ found among cephalopod mollusks that contains a consortium of bacteria, the exact function of which is unknown. To begin to understand the role of this organ, the bacterial consortium was characterized in the Hawaiian bobtail squid, Euprymna scolopes, a well-studied model organism for symbiosis research. Transmission electron microscopy (TEM) analysis of the ANG revealed dense bacterial assemblages of rod- and coccus-shaped cells segregated by morphology into separate, epithelium-lined tubules. The host epithelium was morphologically heterogeneous, containing ciliated and nonciliated cells with various brush border thicknesses. Hemocytes of the host's innate immune system were also found in close proximity to the bacteria within the tubules. A census of 16S rRNA genes suggested that Rhodobacterales, Rhizobiales, and Verrucomicrobia bacteria were prevalent, with members of the genus Phaeobacter dominating the consortium. Analysis of 454-shotgun sequencing data confirmed the presence of members of these taxa and revealed members of a fourth, Flavobacteria of the Bacteroidetes phylum. 16S rRNA fluorescent in situ hybridization (FISH) revealed that many ANG tubules were dominated by members of specific taxa, namely, Rhodobacterales, Verrucomicrobia, or Cytophaga-Flavobacteria-Bacteroidetes, suggesting symbiont partitioning to specific host tubules. In addition, FISH revealed that bacteria, including Phaeobacter species from the ANG, are likely deposited into the jelly coat of freshly laid eggs. This report establishes the ANG of the invertebrate E. scolopes as a model to examine interactions between a bacterial consortium and its host.     

Exploitation of marine bacteria for production of gold nanoparticles

Background

Gold nanoparticles (AuNPs) have found wide range of applications in electronics, biomedical engineering, and chemistry owing to their exceptional opto-electrical properties. Biological synthesis of gold nanoparticles by using plant extracts and microbes have received profound interest in recent times owing to their potential to produce nanoparticles with varied shape, size and morphology. Marine microorganisms are unique to tolerate high salt concentration and can evade toxicity of different metal ions. However, these marine microbes are not sufficiently explored for their capability of metal nanoparticle synthesis. Although, marine water is one of the richest sources of gold in the nature, however, there is no significant publication regarding utilization of marine micro-organisms to produce gold nanoparticles. Therefore, there might be a possibility of exploring marine bacteria as nanofactories for AuNP biosynthesis.

Results

In the present study, marine bacteria are exploited towards their capability of gold nanoparticles (AuNPs) production. Stable, monodisperse AuNP formation with around 10?nm dimension occur upon exposure of HAuCl₄ solution to whole cells of a novel strain of Marinobacter pelagius, as characterized by polyphasic taxonomy. Nanoparticles synthesized are characterized by Transmission electron microscopy, Dynamic light scattering and UV-visible spectroscopy.

Conclusion

The potential of marine organisms in biosynthesis of AuNPs are still relatively unexplored. Although, there are few reports of gold nanoparticles production using marine sponges and sea weeds however, there is no report on the production of gold nanoparticles using marine bacteria. The present work highlighted the possibility of using the marine bacterial strain of Marinobacter pelagius to achieve a fast rate of nanoparticles synthesis which may be of high interest for future process development of AuNPs. This is the first report of AuNP synthesis by marine bacteria.     

Neutralization potential of the plasma of HIV-1 infected Indian patients in the context of anti-V3 antibody content and antiretroviral theraphy

We assessed the anti-V3 antibody content and viral neutralization potential of the plasma of 63 HIV-1-infected patients (antiretroviral naïve=39, treated=24) against four primary isolates (PIs) of clade C and a tier 1 clade B isolate SF162. Depletion and inhibition of anti-V3 antibodies in the plasma of five patients with high titers of anti-V3 antibodies led to modest change in the neutralization percentage against two PIs (range 0–21%). The plasma of antiretroviral-treated patients exhibited higher neutralization potential than that of the drug-naïve plasmas against the four PIs tested which was further evidenced by a follow-up study.     

Is There Any Association between Use of Smokeless Tobacco Products and Coronary Heart Disease in Bangladesh?

Background

Most epidemiological studies exploring the association between smokeless tobacco (SLT) use and coronary heart disease (CHD) have been in Western populations, and have focused on SLT products used in those countries. Few studies come from South Asian countries. Our objective was to determine the association between SLT use and CHD among non-smoking adults in Bangladesh.

Methods

A matched case-control study of non-smoking Bangladeshi adults aged 40–75 years was conducted in 2010. Incident cases of CHD were selected from two cardiac hospitals. Community controls, matched to CHD cases, were selected from neighbourhoods, and hospital controls were selected from outpatient departments of the same hospitals. The Rose Angina Questionnaire (RAQ) was also used to re-classify cases and controls.

Results

The study enrolled 302 cases, 1,208 community controls and 302 hospital controls. Current use was higher among community controls (38%) compared to cases (33%) and hospital controls (32%). Current use of SLT was not significantly associated with an increased risk of CHD when community controls were used (adjusted OR 0.87, 95% CI 0.63–1.19), or when hospital controls were used (adjusted OR 1.00, 95% CI 0.63–1.60), or when both control groups were combined (adjusted OR 1.00, 95% CI 0.74–1.34). Risk of CHD did not increase with use of individual types except gul, frequency, duration, past use of SLT products, or using the RAQ to re-classify cases and controls. There was a significant association between gul use and CHD when both controls were combined (adjusted OR 2.93, 95% CI 1.28–6.70).

Conclusions

There was no statistically significant association between SLT use in general and CHD among non-smoking adults in Bangladesh. Further research on the association between gul use and CHD in Bangladesh along with SLT use and CHD in other parts of the subcontinent will guide public health policy and interventions that focus on SLT-related diseases.     

Heterotrophic nitrification by <Emphasis Type="Italic">Achromobacter xylosoxidans</Emphasis> S18 isolated from a small-scale slaughterhouse wastewater

Heterotrophic carbon utilizing microbes were acclimatized in the laboratory by inoculating sludge collected from the waste discharge pond of a small-scale rural abattoir in India in a nutrient solution intermittently fed with glucose and ammonium chloride. Cultures of 10 well-developed isolates were selected and grown in a basal medium containing glucose and ammonium chloride. Culture supernatants were periodically analyzed for ammonium nitrogen (NH₄ ⁺-N) and chemical oxygen demand (COD). Polyphasic taxonomic study of the most active nitrifier (S18) was done. Half saturation concentration (K _s), maximum rate of substrate utilization (k), yield coefficient (Y) and decay coefficient (K _d) were determined from the Lineweaver–Burk plot using the modified Monod equation. S18 was able to remove 97 ± 2% of (NH₄ ⁺-N) and 88 ± 3% of COD. Molecular phylogenetic study supported by physiological and biochemical characteristics assigned S18 as Achromobacter xylosoxidans. Nitrification activity of A. xylosoxidans was demonstrated for the first time, while interestingly, the distinctive anaerobic denitrification property was preserved in S18. K _s values were determined as 232.13 ± 1.5 mg/l for COD reduction and 2.131 ± 1.9 mg/l for NH₄ ⁺-N utilization. Yield coefficients obtained were 0.4423 ± 0.1134 mg of MLVSS/mg of COD and 0.2461 ± 0.0793 mg of MLVSS/mg of NH₄ ⁺-N while the decay coefficients were 0.0627 ± 0.0013 per day and 0.0514 ± 0.0008 per day, respectively. After a contact period of 24 h, 650 ± 5 mg/l solids were produced when the initial concentration of COD and NH₄ ⁺-N were 1820 ± 10 mg/l and 120 ± 5.5 mg/l, respectively. This is the first report on the kinetic coefficients for carbon oxidation and nitrification by a single bacterium isolated from slaughterhouse wastewater.     

Computational validation of 3-ammonio-3-(4-oxido- 1H-imidazol-1-ium-5-yl) propane-1, 1-bis (olate) as a potent anti-tubercular drug against mt-MetAP

The advent of Multi Drug Resistant (MDR) strain of Mycobacterium tuberculosis (TB) necessitated search for new drug targets for the bacterium. It is reported that 3.3% of all new tuberculosis cases had multidrug resistance (MDR-TB) in 2009 and each year, about 0.44 million MDR-TB cases are estimated to emerge and 0.15 million people with MDR-TB die. Keeping such an alarming situation under consideration we wanted to design suitable anti tubercular molecules for new target using computational tools. In the work Methionine aminopeptidase (MetAP) of Mycobacterium tuberculosis was considered as target and three non-toxic phenolic=ketonic compounds were considered as ligands. Docking was done with Flex X and AutoDock 4.2 separately. Ten proven inhibitors of MetAP were collected from literature with their IC50 and were correlated using EasyQSAR to generate QSAR model. Activity of ligands in question was predicted from QSAR. Pharmacophore for each docking was generated using Ligandscout 3.0. Toxicity of the ligands in question was predicted on Mobyle@rpbs portal and Actelion property explorer. Molecular docking with target showed that of all three ligands, 3-ammonio-3-(4-oxido-1H-imidazol-1-ium-5-yl) propane-1, 1-bis (olate) has highest affinity (- 37.5096) and lowest IC50 (4.46 µM). We therefore, propose that -3-ammonio-3-(4-oxido-1H-imidazol-1-ium-5-yl) propane-1,1- bis(olate) as a potent MetAP inhibitor may be a new anti-tubercular drug particularly in the context of Multi Drug Resistant Tuberculosis (MDR-TB).